A Storm's Coming
by Not-completely-human
Summary: Harry Potter is not the Boy-Who-Lived, his twin brother was chosen instead. At the age of 5 years old, Harry decides he has had enough of his life, and runs away. With no real plan of where to go, he accepts help from a mysterious stranger, and forges a new life. But he never forgot the world he was born into. Now, they need his help. Will he let them endure the storm on their own?
1. Chapter 1

**Author's Note: Hi everyone! so, I'm new to , and this is my first published story! I don't know how long it will be between updates (I'm not very good at time management), so please have patience. I will accept constructive criticism, and try to take your advice into account. Flames, however, will be ignored. I hope you enjoy!**

 **Disclaimer: I do not own either the Harry Potter or the Percy Jackson universe, both belong to their respective authors (J.K. Rowling and Rick Riordan)**

"Percy! Chiron needs you in the Big House!" I tried not to groan as I heard Grover's voice. We just got done fighting the war with Gaea, and I was ready for a break. Especially after my nose almost destroyed the world (that's long story). Reluctantly, I put the cap on riptide, and turned to leave the arena. As I walked towards the Big House, I wondered what Chiron could possibly need from me. As far as I know, there are no madmen trying to take over the world, no lightning bolts stolen, no dark, evil wizards- no. Don't think about that, I scolded myself. You left that place years ago.

I walked through the door and froze. Chiron was sitting in his wheelchair talking to three people I had hoped to never see again. An old man with a long white beard, half-moon glasses, and a maddening twinkle in his eyes. Two adults wearing robes, one with hazel eyes and messy black hair, like my own. The other with longer hair, and blue eyes. I was turning on my heel to leave when Chiron spotted me.

"Percy, come on in. There are some people I would like you to meet." Chiron's voice was jovial, but I could detect an underlying tone of confusion about why I had tried to leave. These people couldn't be here. They had ruined part of my childhood, and I wasn't going to let them ruin the new life I had.

 _~flashback~_

 _It was a cold Halloween night, and Lily and James Potter were at a party. They had left their twin sons Harry and Oliver in the care of an old woman by the name of Arabella Fig. There was a sharp crack as Voldemort appeared in Godric's Hollow. He fingered his wand as he slowly stalked towards the house. The couple that lived there was foolish to think that they could trust their so-called "friend" Peter Pettigrew. And to leave the children in the care of a squib, it was like they were asking him to attack them. Slowly, Voldemort pushed open the door. The old lady that had been dozing in the armchair started to scream, then was silenced._

 _"Avada Kedavera"_

 _Voldemort moved towards the stairs, where he heard the sound of crying coming from the nursery, Entering the room, he saw two cribs, each holding a one year-old boy. The child on the left, Oliver Sirius Potter, had auburn hair, and hazel eyes, and was currently doing his best to scream his lungs out. In contrast, Harry James Potter, the boy on the right had black hair, and sea-green eyes. This boy was staring at the Dark Lord curiously, as if wondering what he was doing in the boy's house. His eyes held a depth that made it seem as if Voldemort was staring into a fathomless ocean. Surely, the Dark Lord thought, the boy on the right was the child of the prophecy, the one destined to destroy him. Taking his time, Voldemort raised his wand and pointed it directly into Harry's face._

 _"Goodbye, Harry Potter. Avada Kedavera!" Voldemort watched as the green light sped towards the boy, and the his expression of glee turned to one of horror when a green shield erupted around the boy, reflecting the curse and allowing only a tiny part of it to slip through and hit the boy in the forehead. As the killing curse rebounded, Voldemort screamed in pain, than disappeared. The shield expanded to cover Oliver as the roof came down, but not before a piece of sharp plaster sliced his palm in the shape of a "V"._

 _"When James and Lily returned to the house half an hour later, they were dismayed at the sight of the demolished house and ran inside, frantically calling for their sons. To their relief, the sound of crying came from the nursery, and they rushed inside to find both boys shaking but not hurt._

 _"James, go floo Dumbledore, tell him what happened," Lily instructed. James ran off and returned minutes later with the bearded wizard._

 _"Lily, may I see the children for a moment? We need to determine which of them the child of the prophecy is." Dumbledore asked, his eyes twinkling. Reluctantly, Lily handed over the children. Dumbledore saw the mark on Oliver's hand and immediately declared him the boy-who-lived. He failed to notice the lightning bolt scar on young Harry's forehead, and the dark aura that surrounded it._

 _From that day on, Oliver Potter was loved and cherished by his parents and godfather, Sirius Black, while Harry was shoved to the side. Oliver loved the spotlight, and was considered an angel. He never hesitated to blame Harry for any wrong-doings he committed. Harry was ignored much of the time, except when he did something wrong. By the time the twins were five, he had had enough._

 _In the middle of the night, the boy packed a small bag and snuck out of the house. He ran and ran, with no clue where he was going, until he couldn't run anymore. There, in the middle of the street, he collapsed and cried. A fresh sea breeze surrounded him, and a man in a Hawaiian shirt and Bermuda shorts appeared before him. Harry was so startled that he stopped crying._

 _"Hello, Harry," the man said._

 _"H- hello," Harry whispered. The man stared at him sadly for a moment before speaking again._

 _"No one should have to live the life you do. I can give you a home, if you would like. There is a woman I know who always wanted a child. She would love to take you in."_

 _Harry stared suspiciously at the man, but for some reason felt that he could be trusted. "Yes, please." Harry whispered. The man stooped down and gathered the boy in his arms, and then they were gone._

 _They arrived in a small apartment, where a brown-haired, kindly-looking woman was sitting sipping tea. She immediately jumped up at the sight of them, somewhat startled._

 _"Harry, this is Sally Jackson. She is the woman I spoke of." Harry shyly got down from the man's arms, and looked up at Sally. Sally's heart melted at the sight of him._

 _"Hello," he whispered. Sally pulled him into her arms, noticing his body stiffen, then relax._

 _"Sally will be your new mother, if you wish it." The man said._

 _Harry looked up, beaming, and nodded his head. Timidly, he spoke, "may I have a new name?" he asked._

 _"Of course, dear," Sally said, "What do you think of Perseus? Perseus Jackson."_

 _~Flashback ends~_

"Percy? Percy, are you alright?" I snapped back to reality at the sound of Chiron's voice. "Percy, this is-"he started, but I cut him off.

"Get Annabeth," my voice came out cold and hard, unlike my usually joking and playful tone. Chiron was taken aback.

"Percy, what do you mean?" he asked.

"You know as well as I do that she is the only one that can reign me in when I lose my temper," I said. A new voice came from the corner.

"No need, I'm already here," said Annabeth, taking off her Yankee's cap. "Now, seaweed brain, be quiet and let Chiron introduce our guests," she said moving to stand next to me. We sat on the couch as Chiron introduced the "guests".

"Percy, Annabeth, this is Albus Dumbledore, James Potter, and Sirius Black. This may come as a shock, but magic is real and they are wizards." I fought to keep my expression blank. Annabeth didn't look surprised. She probably already knew, being a daughter of Athena and all. Chiron went on to explain how their Dark Lord was back, and that they wanted one demigod to come to Britain and help protect the "chosen one" Oliver Potter. As soon as Oliver's name left his lips, my hands clenched into fists. "So, Percy, I thought that you would be the best one for the job, as you are close in age to Oliver, and a Hero of Olympus." Chiron concluded. I turned to the wizards.

"Give me one good reason why I shouldn't kill you." My voice was icy, and I knew my eyes were flashing with rage. Chiron looked appalled, and Annabeth studied me, trying to figure out why I hated these people. The guests looked shocked, then scoffed, as if I could never hurt them. Faster than they could blink, I had my sword to James's throat. Everyone froze.

Annabeth jumped up and slowly guided my hand so that I wasn't poised to kill anyone, then led me back to my seat and I slumped down, not meeting anyone's eyes.

"My dear boy," Dumbledore started, "why on earth would you want to hurt us? We have never done anything to you." The old man's eyes held curiosity, and a pinch of wariness.

"I am not and never will be 'your boy'," I spat the words, "and if I had a choice you and your companions would leave with no memory of this place and quite possibly a concussion." My glare was so intense that they backed away. Annabeth put a hand on my arm.

"Percy, what are you talking about? Have you met these people before?" I could clearly read the concern on my girlfriend's face, and I relaxed a little.

"I'll tell you in private, come on," I said. As we left the room, I heard Chiron apologizing, saying I wasn't usually like this. Annabeth and I walked down the hall and into the room that we used for senior counselor meetings. After staring at each other for a moment, I explained everything. How I was a wizard, and a demigod. How the man in there was my "father", and how he had overlooked me in favor of my twin. How I ran away and the man that I now knew to be Poseidon had found me and taken me to Sally, who became my mother. I told her everything, including the beatings I would get when I did something wrong, and the way I was ignored when I did something right. By the time I had finished, Annabeth's eyes were flashing murderously, and I was shaking. Slowly, she brought me in for a hug.

As we walked back into the main room where Chiron was, Annabeth snapped. A dagger embedded itself in the wall next to James' head, and a fist collided with his jaw. Reluctantly, I pulled her back.

"As amusing as this is, I think I've decided we don't need to kill them," I told her.

"You can't kill me! I'm the auror James Potter, father and trainer of the boy-who-lived! I could beat you easily," James scoffed. Annabeth hissed.

"Shut up or next time the dagger will be in your head, instead of beside it." The foolish man was about to retort, but I intervened.

"So James, how is your son?" I asked. He looked surprised but answered nonetheless.

"Oliver is amazing! I'm sure you two will get along gre-" I cut him off.

"Not Oliver. Your other son." My voice had a dangerous tone that even James seemed to pick up on.

"What other son? There was another boy once, but he ran away twelve years ago. And good riddance. He was stupid, worthless, ugly, attention-seeking, and always trying to take credit for things Oliver did! I was glad when he disappeared. He was weird too, had a strange scar on his forehead." By the time James' rant was done, I was beyond pissed.

"Oh, you mean the boy you hit, starved, ignored, and neglected? That boy?" James turned pale. "Well guess what, he was glad to be gone! And he hoped to never see any of you again, because he knew that if he did he just might kill you." With that,I spun around and walked out, Annabeth on my heels.

Eventually, my feet brought me down to lake, where I collapsed on the beach, Annabeth beside me. We just sat there for a while, not talking, just taking comfort in each other's presence. Finally, she broke the silence.

"You know we have to help them, right? It's the right thing to do. " I looked over, meeting her steely grey eyes.

"I know. I just never thought I would have to go back there. Never thought I would have to see any of them again." My voice faded near the end, and Annabeth brought me in for a hug. Suddenly, her head shot up, grey eyes sparkling, as they always do when she gets an idea.

"Percy!" she exclaimed, "They said they wanted ONE demigod right?" I nodded glumly. "Well, what if we agreed to help them, but only on our terms. We can bring our friends, they are not able to have any control over us. You don't even have to tell them your former identity if you don't want to!" slowly, I started to smile.

"C'mon. Let's go back to the Big House and tell Chiron. We can pick everyone else up on the way." We scrambled to our feet, and ran around the camp to find everyone and tell them our plan. Thalia, Piper, Jason, Leo, Frank, Hazel, Nico, Connor and Travis, Clarisse, Will, and Calypso agreed to help us after my explanation. Clarisse looked murderous, wondering how anyone could do that to a five year old boy, Nico seemed darker than usual, Piper and Hazel had tears in their eyes while Jason and Frank tried to comfort them. Thalia seemed to be in a state of shock, and I warily avoided Will in case he tried to make me visit to the infirmary to "check for any lasting damage". Calypso just stood by Leo, trying to keep him from bursting into flames. The Stolls wore grins that I knew all too well, and I vowed to keep off their bad side for a while.

Chiron and the three wizards looked shocked when we all burst back into the room. After asking to speak with Chiron in private and telling him the same story I told Annabeth and the others, he agreed that our plan was a good idea. We walked back into the room just in time to stop Leo from setting it on fire and Clarisse from giving the wizards a taste of her electric spear (I kinda wish we hadn't stopped that one, actually).

"It seems there has been a slight change in plans," Chiron forced a smile as he addressed the wizards, "there shall be 14 demigods going with you to Britain. This is the only way you will get any of our help." James and Sirius looked like they were going to protest, but Dumbledore intervened.

"Very well, the more the merrier. We will be leaving tomorrow, so I suggest you children all get some rest." He and James turned to leave, but Sirius lingered behind. After they were gone, he approached me.

"I'm sorry, Percy, was it?" I gave a short nod. "I was just wondering if you could tell me how you knew about Harry." I almost refused, but the look in his eyes, desperate and regretful, made me give in.

"I met him on a quest sometime back, we got to talking and exchanged stories."

"if you ever see him again, could you please tell him that I'm sorry for the way I acted, and that I wish I could change what happened? I looked for him the longest you know, I just stopped looking two years ago." His mournful face told me that he was telling the truth, that he really was sorry, and he did keep looking after everyone else gave up.

"I'll tell him," I promised. Sirius turned to leave, and I stood quietly, watching him go.


	2. Chapter 2

**Author's Note: Hey guys, sorry it's been so long. I finally have a new chapter done. It's not as long as the last one (sorry). I hope you like it.**

 **Disclaimer: I do not own either Harry Potter or Percy Jackson, both belong to their respective authors (J.K. Rowling and Rick Riordan)**

All of us demigods spent most of the night packing for our trip into the wizarding world. I packed lightly, as I hoped that we wouldn't be staying very long. I simply threw a few t-shirts, a couple pairs of jeans, some socks and underwear, and the standard demigod survival materials (nectar and ambrosia, a dagger, a few small knives, just normal stuff), into a blue duffel bag. Looking around my cabin, I realized how few things I actually had at camp.

Deciding I was done, I went over to the Athena cabin to find Annabeth. I know what you're thinking, shouldn't he have been going to bed? Well, the thing is, ever since my and Annabeth's "vacation" in Tartarous, we've been having nightmares. The only thing that helps is sleeping close to each other. Normally, that would be a problem at camp, but I guess Chiron had decided to let it pass so that we wouldn't wake the whole camp up with screams (again…).

"Hey Malcolm," I said as the blond boy opened the door right as I raised my fist to knock.

"Annabeth is in the back," he told me, not even bothering to ask why I was there.

"Thanks," I nodded to him as I went past and forged my way through all the bulletin boards, diagrams, and stacks of books. Thankfully, I managed to make my way to Annabeth without knocking over a single stack (that would've been EXTREMELY bad). When I finally saw her, my beautiful girlfriend was rummaging around in her desk drawers, muttering to herself, and pulling out so many notebooks, binders, and sheets of loose paper that it seemed like she would drown in it.

Sneaking up behind her, I quickly placed my hands over her eyes. Unfortunately, it only occurred to me at the last second that it might not have been the wisest decision to do so. Alas, it was too late to stop the action. Next thing I knew, I was on the ground with Annabeth's knee on my chest and her drakon bone sword to my throat. Looking into her glaring grey eyes, I internally flinched.

"Percy!" she yelled. "Don't do that!" this time, I visibly winced. Her eyes softened, just a little, but it still counts. Seeing my chance, I gave her a hopeful half smile and my patented puppy dog look.

"Sorry, Annabeth," I said sheepishly. "I won't do it again." Her glare finally broke, and she (albeit somewhat reluctantly) let me up.

"You'd better not," I could hear the "or else" that was implied, and gulped, nodding obediently. My girlfriend sure could be scary when she wanted to. Then again, I already knew that.

"So, are you almost done packing?" I asked.

"Sort of," she replied, "I still need to pack my blueprints, and the magic textbooks I got from the Hecate cabin. And then there's the 'in case of emergency' materials, and I need to find my other tennis shoes…" she trailed off into silence, her eyes becoming clouded with thought.

"You can finish packing in the morning, Wise Girl, we need sleep if we're going to be ready to leave in the morning," I said gently. "I'll help you get the rest of your stuff, then we need to go to bed."

"I suppose that you're right," she sighs, "and don't get used to it, you're still a Seaweed Brain." she added as an afterthought, seeing my smug look. Well, there goes that. I knew it was just too good to last. I pouted for a moment, then started helping Annabeth gather her packed bags and find the other things she was missing still. After she was satisfied with her packing (Finally! It takes sooooo long! OOPS! She saw the look on my face and guessed what I was thinking! AHH!), I grabbed one of her bags while she took the other and we headed over to my cabin to sleep. We used to alternate cabins, but her siblings complained that I snored too much (and Malcolm said I still drool).

I opened the door and we set her bags down next to my backpack by the doorway. I caught a disapproving look being sent my way, and somehow I knew I would end up with at least a duffel bag before we left in the morning. I walked over to the bed and lay down, facing Annabeth. "Come on, Wise Girl. We gotta have you sharp in the morning."

She gave a look that said, "I'm always sharp, and if you think I'm not, my blade surely is", but she came over and lay down next to me anyway. She snuggled into me and I wrapped my arms around her.

"Good night Wise Girl."

"G'night Seaweed Brain.

In the morning I woke to light flooding into the cabin. And a bucket of ice cold water in my face. Luckily for me, I don't get wet unless I want to get wet. So a bucket of water is not the best way to wake me up. Looking around for the culprit, I spotted Leo running out the door with a bucket in his hand. I scanned the room for Annabeth, and found her standing by a blue duffle bag which I assumed was filled with my clothes and anything else she determined essential.

"Oh good, you're finally awake. Help me carry all of this up to the hill, we're almost late," she said by way of greeting.

"Well good morning to you too sunshine," I grumbled. But nevertheless, I stood up and grabbed a couple bags from her hands. I was about to head out the door when she stopped me.

"Percy, aren't you forgetting something?" I looked down and saw my pajamas.

"Oh yeah. Hehe, oops," I rubbed the back of my neck sheepishly.

"Get changed, I'll meet you outside." She strode out the door as I turned back to my dresser. I saw a set of clothes laid out on top of it. Apparently, my girlfriend doesn't trust me to pick out my own clothes. Looking in my drawers, I saw that she had good reason not to. Annabeth had taken the liberty of packing all my decent clothing and all that was left in the drawers were ripped jeans and t-shirts with holes in them (even though those are the most comfortable in my opinion). After I threw on the clothes Annabeth had left me, I met her outside my door and we walked up to the hill. I saw all the other demigods that were going with us already gathered there. Smirking, I snapped my fingers and drenched Leo in seawater.

"DUDE! NOT COOL!" he yelled at me. Frank started snickering.

"I told you not to try and wake him up with a bucket of water," Calypso told Leo.

"Aw, come on! No one messes with the Super-Sized McShizzle!" Leo started flexing, and generally making a fool of himself.

"Is that so, runt?" questioned Clarisse. She was fingering her electric spear. Leo gulped and backed away.

"Um…yes?" he squeaked before running off to hide behind Piper. "Pipes help me! I've pissed off the scary Ares girl!" he stage whispered. Piper just looked at him, unimpressed.

"Now children, calm down," Chiron came up the hill in his wheelchair, Dumbledore, James Potter, and Sirius Black following in his wake. Everyone glared at the wizards, and I made awkward eye contact with Sirius before looking away. "You will be traveling to England via a magical device called a portkey," Chiron explained as he help out an old newspaper. "All of you must place a finger on this paper, and then off you go."

Seeing the apprehensive looks on my friends' faces, I surprised everyone by being the first to move forward and place a finger on the paper. After a nod from me, Annabeth and Thalia followed my example. The rest of the group cautiously followed their example. The three wizards also moved forward and touched the portkey.

"Best of luck to you all," said Chiron, meeting my eyes.

"And we're on our way," said Dumbledore, that damnable twinkle in his eye. Everything started spinning and my vision went black for a moment before my feet touched ground.

"Welcome, guests, to Number 12 Grimmauld Place."

 **P.S. Author's Note: this is probably how most of my updates will be, I'm sorry but I am really not good with schedules (especially when writing)**


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